curriculum for participatory learning and action research (plar) for integrated rice management...

Curriculum for Participatory Learning and

Action Research

(PLAR)

for

Integrated Rice Management

(IRM)

in Inland Valleys of Sub-Saharan Africa

Marco C.S. Wopereis, Toon Defoer, Philip Idinoba, Salif Diack

and Marie-Josèphe Dugué

CGIAR

Africa Rice Center (WARDA)

Technical Manual

ISBN 92 9113 325 6 (Print)

ISBN 92 9113 324 8 (PDF)


The Africa Rice Center is an autonomous intergovernmental agricultural research association of

African member states and one of the 15 international agricultural research centers supported by the

Consultative Group on International Agricultural Research (CGIAR).

Its mission is “to contribute to poverty alleviation and food security in Africa, through research,

rice sector in ways that ensure the sustainability of the farming environment.”

The modus operandi of the Africa Rice Center is partnership at all levels. The Africa Rice Center’s research and

development activities are conducted in collaboration with various stakeholders—primarily the national agricultural

research systems (NARS), academic institutions, advanced research institutions, farmers’ organizations, non-

as well as the millions of African families for whom rice means food.

The development of the ‘New Rice(s) for Africa,’ or NERICA(s), for which WARDA was conferred the CGIAR

African with Asian rice species has helped to shape the Center’s future direction, extending its horizon beyond West

and Central Africa into Eastern and Southern Africa. The creation of NERICA rice and its expected contribution to

food security and income generation in Sub-Saharan Africa are in harmony with the spirit and sustainable-development

aspirations of the World Summit on Sustainable Development (WSSD), the Tokyo International Conference on

Africa’s Development (TICAD), the Millennium Development Goals (MDGs), and the New Partnership for Africa’s

Development (NEPAD).

The Africa Rice Center hosts four networks and consortia—the African Rice Initiative (ARI), the Inland Valley

Consortium (IVC), the International Network for Genetic Evaluation of Rice in Africa (INGER-Africa), and the

West and Central Africa Rice Research and Development Network (ROCARIZ)—all charged with ensuring the

widespread and rapid dissemination, adoption and diffusion of new rice cultivars across the various rice ecologies

found in Africa.

The Africa Rice Center has its headquarters in Côte d’Ivoire and four regional research stations—one covering the

Sahel and located near St-Louis, Senegal, one at the International Institute of Tropical Agriculture (IITA) in Ibadan,

Nigeria, the third at Dar-es-Salaam, Tanzania, and in Cotonou, Benin, where the center also has its temporary

headquarters.

For more information, please visit www.warda.org

IFAD–International Fund for Agricultural Development

1977 as one of the major outcomes of the 1974 World Food Conference. The main objective of the Fund is

to directly give funds and mobilize additional resources for programmes facilitating economic promotion of

the rural poor particularly by increasing the productivity of agricultural and extra-agricultural activities.

CBF–Inland Valley Consortium

IVC was founded in 1993 to promote sustainable development of inland valleys in Sub-Saharan

Africa. The Consortium groups national and international agricultural research institutes and

development agencies. Since April 1999, the Consortium is part of WARDA and works with 10 West

African countries (Benin, Burkina Faso, Cameroon, Côte d’Ivoire, Ghana, Guinea, Mali, Nigeria,

Sierra Leone, Togo) and 8 international institutions (WARDA, IITA, ILRI, FAO, WECARD/

CORAF, WUR, CIRAD, IWMI). Each of the member states has a National Coordination Unit

(NCU) that brings together—under the direction of a national coordinator—the representatives of

the institutions involved in the development of inland valleys. Donors of the IVC are mainly The

Netherlands (DGIS), France (Ministry of Foreign Affairs), the Common Fund for Commodities

(CFC) and the European Union.

Founded by His Highness the Aga Khan in 1967, the Aga Khan Foundation (AKF)

has been experimenting with, and implementing, innovative solutions to development

challenges for over 40 years. In every undertaking, the overriding goal is to assist in the

struggle against hunger, disease, illiteracy, ignorance and social exclusion. Central to all

these efforts have been inclusive, community-based development approaches, in which

local organisations identify, prioritise and implement projects with the Foundation’s

health, education, civil society and the environment. For more information, please see

www.akdn.org/.

IFAD

Inland Valley Consortium

Consortium bas-fonds

AGA KHAN FOUNDATION

Curriculum for Participatory Learning and

Action Research

(PLAR)

for

Integrated Rice Management

(IRM)

in Inland Valleys of Sub-Saharan Africa

Technical Manual

Marco C.S. Wopereis

Toon Defoer

Philip Idinoba

Salif Diack

Marie-Josèphe Dugué

Published by:


2009


CGIAR

© Copyright Africa Rice Center (WARDA) 2009.

WARDA encourages fair use of this material. Proper citation is requested.

Wopereis, M.C.S., T. Defoer, P. Idinoba, S. Diack and M.J. Dugué, 2008. Participatory Learning and

Action Research (PLAR) for Integrated Rice Management (IRM) in Inland Valleys of Sub-Saharan

Africa: Technical Manual. WARDA Training Series. Cotonou, Benin: Africa Rice Center. 128 pp.

Cette publication est aussi disponible en français, sous le titre : Curriculum d’apprentissage participatif et

recherche action (APRA) pour la gestion intégrée de la culture de riz de bas-fonds (GIR) en Afrique sub-

saharienne. Manuel technique.

ISBN 92 9113 3256 (print)

ISBN 92 9113 3248 (PDF)


01 B.P. 2031

Cotonou

Benin

Telephone (229) 21350188

Fax (229) 21350556

E-mail [email protected]

Website http://www.warda.org/

Printing and binding: Pragati Offset Pvt. Ltd., Hyderabad, India.

Contents

Foreword .................................................................................................................................................... iv

Why this manual?..................................................................................................................................................v

Contributors .................................................................................................................................................... vi

Acknowledgements ............................................................................................................................................. vii

Reference 1 - Selecting PLAR-IRM sites ...........................................................................................................1

Reference 2 - Hydrological network, inland valley catchments and lowlands ....................................................3

Reference 3 - Different types of soil ...................................................................................................................8

Reference 4 - Iron toxicity ................................................................................................................................13

Reference 5 - Water control structures for inland-valley lowlands .................................................................15

Reference 6 - The seasonal work plan ............................................................................................................22

Reference 7 - Field water management ...........................................................................................................24

Reference 8 - Knowing the rice plant ...............................................................................................................26

Reference 9 - Seed production ........................................................................................................................33

Reference 10 - Selecting a variety ......................................................................................................................36

Reference 11 - Effects of temperature on rice development ..............................................................................39

Reference 12 - Field preparation before the start of the rice-growing season ...................................................43

Reference 13 - The seedling nursery .................................................................................................................45

Reference 14 - Plant nutrients ............................................................................................................................49

Reference 15 - Integrated soil fertility management ...........................................................................................52

Reference 16 - Transplanting .............................................................................................................................63

Reference 17 - Farmers’ experimentation ..........................................................................................................65

Reference 18 - Getting acquainted with weeds of rice .......................................................................................72

Reference 19 - Integrated weed management....................................................................................................75

Reference 20 - Safe and correct use of herbicides.............................................................................................77

Reference 21 - Insects in rice cropping...............................................................................................................84

Reference 22 - African rice gall midge................................................................................................................95

Reference 23 - Rice stem borers .......................................................................................................................99

Reference 24 - Major diseases in rice ..............................................................................................................105

Reference 25 - Integrated rice disease management ......................................................................................107

Reference 26 - Harvest and post-harvest ........................................................................................................109

Reference 27 - End-of-season evaluation ........................................................................................................112

Photo pages .................................................................................................................................................115

PLAR–IRM Curriculum: Technical Manual (Wopereis et al., 2009).iv

Foreword

The inland valleys of Sub-Saharan Africa are a major asset for the region’s food security and they are particularly well

adapted for rice growing. However, these land resources (an estimated 85,000,000 ha) have often not been developed

gap between rice production and rice consumption on the continent, and also to help stabilize the use of the fragile

upland soils.

The idea of this manual, and of the associated Facilitator’s Manual, stems from the observation that West Africa’s inland

valleys are very complex and that there is a chronic lack of communication among farmers, extension services and

(Agence nationale d’appui au développement rural(( , Côte d’Ivoire), and agricultural research and development services,

including NGOs, in Benin, Côte d’Ivoire, The Gambia, Ghana, Guinea, Mali, Nigeria and Togo.

This Technical Manuall

with all aspects of rice cropping, from land preparation up to the end-of-season evaluation after harvest, using an

integrated rice management approach.

We hope that later issues will offer a more complete curriculum on the integrated management of all the natural

resources in inland valleys. Some references already deal with such topics. Furthermore, we would like to encourage

d’Ivoire, The Gambia, Ghana, Guinea, Mali, Nigeria and Togo, who have contributed to this important work.

Cotonou

Benin

PLAR–IRM Curriculum: Technical Manual (Wopereis et al., 2009). v

Why this manual?

agricultural production. Their surface area has been estimated at 85,000,000 ha, i.e. 7% of the total arable cropland,

of which only 10–15% is actually used for agriculture. Most of the inland valleys are situated in the inter-tropical

zone, where rainfall is more than 700 mm per year. The objective of the two manuals (facilitator’s and technical) is

Saharan African in a sustainable way.

Although the term ‘inland valley’ always refers to wetlands, not all wetlands are inland valleys. In particular, the

term ‘inland valley’ excludes coastal depressions, coastal river deltas, lagoons and mangroves; it also excludes inland

depressions, such as wide alluvial lowland valleys, interior deltas, lake areas, swamps, and deep-water rice zones.

Inland valleys are characterized by their upstream position in a drainage network. The catchment area captures the

water of the whole hydrologic network of an inland valley, from the hillcrest (upland) through the hydromorphic zone

(with shallow groundwater table) to the inland-valley bottom.

This manual focuses on integrated rice management in inland-valley lowlands in the lower part of the watershed.

Here, during the rainy season, rainfall run-off accumulates and the water table is recharged. Because of these wet

makes valuable use of this water resource. The existence of shallow groundwater in some inland valleys also allows

arboriculture and vegetable production.

The inland valleys of Sub-Saharan Africa are extremely diverse and complex; therefore, standard recommendations

are rendered of little use to farmers. The objective of the Facilitator’s Manual is to stimulate discussions within

that manual will help build bridges between local and external knowledge. This Technical Manual, forming a set with

the Facilitator’s Manual

Technical Manual contains technical

references on the options that are available to inland-valley farmers. It was developed with the collaborative work of

Ivorian farmers who cultivate rice in inland valleys with full water control and partial water control.

The sustainable management of inland valleys involves many factors. It requires a holistic view of the entire watershed

and hydrological network. Land use changes in the upland areas (e.g. cutting trees) will affect the inland-valley system

them will adapt them to your own socio-economic and biophysical conditions. It is highly probable that we will together

natural-resources management, in general, for the inland valleys of Sub-Saharan Africa. We will be very grateful to

those who will send their suggestions and comments for future editions.

PLAR–IRM Curriculum: Technical Manual (Wopereis et al., 2009).vi

Contributors

PLAR–IRM Curriculum: Technical Manual (Wopereis et al., 2009). vii

Acknowledgements

The publication of this work was made possible thanks to the following support:

Coopération française

The authors

Marco Wopereis, Toon Defoer, Philip Idinoba, Salif Diack, Marie-Josèphe Dugué

PLAR–IRM Curriculum: Technical Manual (Wopereis et al., 2009). 1

Reference 1 Selecting PLAR-IRM sites

Summary

This reference provides guidelines for choosing inland valleys where the participatory learning and action

research (PLAR) approach for integrated rice management (IRM) will be implemented. This is a very important

step which will largely determine the probability of success and the ease with which results obtained can be

diffused.

Each inland valley is a complex entity in which biophysical, agricultural, human, socio-organizational

through farmer-to-farmer training (see Facilitator’s Manual

Size and diversity of the target area

of intervention sites at the start to gain experience and to ensure that the approach is properly

Inland-valley typology

Representativeness

valleys with the same or a similar typology to facilitate extension of PLAR-IRM to neighboring

Accessibility

PLAR-IRM sessions because of bad weather, and to facilitate diffusion of PLAR-IRM to neighboring

PLAR–IRM Curriculum: Technical Manual (Wopereis et al., 2009).2

Reference 1Selecting PLAR-IRM sites

Distance to the site

Prior knowledge of the area

Degree of water control

Social cohesion

based on collective learning and implementation of collective activities, such as the maintenance of

Such cohesion may be lacking, for example, where inland-valley lowlands are jointly exploited by

Farmer organization

Bibliography

IDS Discussion Paper

Introduction à la méthode accélérée de recherche

participative (MARP)

Participatory Rapid Appraisal for Community Development: A training manual

based on experiences in the Middle-East and North Africa


Reference 2 Hydrological network, inland valley

catchments and lowlands

and central Africa, as fadamas in northern Nigeria and Chad, bas-fonds or marigots in francophone

catchment area captures the water of the whole hydrological network of an inland valley, from the crest

hydrological network has consequences for

its sustainable development, ensuring a good

A good knowledge of the hydrological

functioning of the catchment area will help

in the management of the inland-valley

Summary

This reference addresses the principles of a hydrological network, inland-valley catchments and lowland areas,

and how they are linked. This information is important for water management and inland-valley development

planning.

bottom of the inland valley


Figure 2.2. First-, second- and

third-order inland valleys

Reference 2Hydrological network, inland-valley catchments and lowlands

Hydrological network

A typical hydrological network has many watersheds and wetlands of different sizes, which can be

A is located at the beginning of the network, which means that there are no

A

order valley

3 order valley


A

The inland-valley catchment area

elements of the toposequence of a small valley are the upland area, the hydromorphic fringe and the

can often observe stains on the water that resemble oil spills—these are due to the presence of



Type of inland valleys and valley bottom

Narrow valleys with relatively steep and straight to convex side-slopes, occurring in relatively hard

Intermediate valleys with moderately steep, concave side-slopes, in moderately hard rocks (such

on granitic formations

Soils of the valley lowlands vary widely in their characteristics, both within and between valleys, ranging


Head

Exit

Figure 2.3. Representation of a

longitudinal transect in a small va

showing its head (upstream), cen

exit (downstream)



Bibliography

The Wetlands and Rice in Sub-Saharan Africa

Mise en valeur et aménagement des bas-fonds

d’Afrique de l’Ouest

Inland Valleys in West Africa: An Agro-ecological Characterization

of Rice-growing Environments


Reference 3 Different types of soil

Summary

Soil is often the most important asset of smallholder farmers in Sub-Saharan Africa. This technical reference

presents the different types of soil, their characteristics and the simple indicators for recognizing them.

the crops that can be cultivated because they will be adapted to the soil and will provide good crop

Figure 3.1. Soil texture

Cl

5 mm

Loamand

Coarse sand


Soil color

colors predominate in topsoil layers, while in the lower layers the colors of iron oxide or manganese

Color changes can provide some indications about the moisture status of the soil, because in dry and

Soil texture

Reference 3Different types of soil


How to observe and determine soil texture

Sandy–

Loamy–

Clayey–

Figure 3.2. Method to determine soil

the texture


Sandy

Loamy

Clayey

Table 3.1 Important soil characteristics and their relation to soil texture

Characteristics Sand Loam Clay

Drainage Fast Average Slow

Retention capacity Low Average High

Capacity to stock nutrients Low Average High

Organic matter content Low Average High

conditions



Soil structure

Soil structure is linked to the organization of primary particles, such as grains of sand, loam and clay in

Bibliography

The Nature and Properties of Soils

Mémento de l’Agronome

Managing Soil Fertility

in the Tropics: A ResourceGuide for Participatory Learning and Action Research

Figure 3.3. Soil aggregates lumps with high organic matter content (1 in dry condition and 3 in moist

condition) are more stable than soil aggregates lumps with a low organic matter content (2 in dry

condition and 4 in moist condition)

1 2 3 4


Farmer Field School on Integrated Soil Management. Facilitator’s Manual

Guidelines for Soil Description

Fundamentals of Soil Science

Booker Tropical Soil Manual. A Handbook for Soil Survey and Agricultural Land Evaluation

in the Tropics and Subtropics

Fertilité des terres de savanne. Bilan de trente ans de recherche et de développement agricole au

sud du Sahara

Properties and Management of Soils in the Tropics



Reference 4 Iron toxicity

Summary

This reference addresses iron toxicity, a serious problem affecting rice growth in inland-valley lowlands,

especially in the moist savanna zone. It is a nutrient disorder associated with high iron concentrations in the

soil solution. All types of inland valleys, with or without water control, may be affected by iron toxicity. This

reference focuses on recognition and causes of iron toxicity and ways to control it.

Observations

The rice plant

bronze–brown and dries out (see

The soil

see

Causes of iron toxicity

soils of the inland-valley bottom, visible red oxidized iron (see

Iron toxicity control


Bibliography

WARDA Annual Report

WARDA Technical Newsletter

International Rice Research Newsletter

Journal of Plant

Nutrition

Reference 4Iron toxicity


Reference 5 Water control structures for inland-

valley lowlands

Summary

The design of a water control system in inland-valley lowlands requires a good understanding of the movement

of water in space and time, and requires engineering skills, which are beyond the scope of this manual.

However, it is useful to have some basic knowledge of the structures that exist so as to better understand

their functioning, development needs and costs, and maintenance requirements. This reference provides an

overview of water control systems commonly in use in West Africa and discusses some of the most basic

maintenance requirements, such as bund repairs, cleaning of canals and land-leveling.

Contour bunds


Reference 5Water control structures for inland-valley lowlands

Figure 5.1. Simple contour bunds

Figure 5.2. Contour bund system with spillway



system is the same as the simple contour-bund system, but it is adapted to situations with high water

Water-retention dikes

Figure 5.3. Water-retention dike


If the permeability of the valley-bottom soils is very high, water losses through seepage underneath

system can be applied (see

Diversion barriers

After being dammed up, the water can be directed into peripheral canals to divert it to the sides of the


A

DivDiv

Figure 5.4. Schematic cross-section of water-retention dike

without (A) and with (B) a seepage barrier


dikes are constructed across the valley bottom in which two outlets are constructed through which the

water, the groundwater level will remain high and crops will use this groundwater as a supplementary

Interception canal system

In very humid areas, it is necessary to increase the drainage of excess water during the main rainy



Small dam system

Maintenance of the development structures

Figure 5.6. Diversion barrier to recharge groundwater

B: dam

P: inlet

D: dikes

Ca: supply canal



Bunds

Canals

Bibliography

Mise en valeur et aménagement des bas-fonds d’Afrique

de l’Ouest, proposition d’un outil d’aide à l’aménagement : le diagnostic rapide de pré-aménagement

(DIARPA).

Agriculture et Développement

Présentation des caractéristiques

Consortium Bas-Fonds



Reference 6 The seasonal work plan

Summary

Guidelines are given on how to develop a work plan for the coming rice-growing season to facilitate time

management and implementation of the cropping calendar.

It is also important to estimate resources needed for maintenance and repairs of the irrigation and

The work plan

Development of the work plan aims to facilitate the organization of the growing season and to avoid


Reference 6The seasonal work plan

Table 6.1 Example of a work plan

No. Date Operations DAT† Development stage Observations

of the plant

1 10/06 Ordering inputs –34

2 23/06 Receiving inputs –21

3 24/06 Flooding before

4 28/6 First plowing; Installation

of the nursery –16

5 29/06 Flooding before second

plowing –15

6 12/07 Harrowing and

leveling; Basal fertilizer –2

7 14/07 Beginning of

transplanting 0

8 30/07 Herbicide application 16 Start of tillering

9 01/08 Urea fertilizer 1 18 Start of tillering

10 Etc.

11

12

† DAT = Days after transplanting (for days before transplanting, use the negative sign).


Reference 7 Field water management

Summary

infrastructure. Good water management is based on good leveling and on the possibility to get water into and

transplanted rice. The crop-establishment mode usually encountered in inland-valley lowlands presents the

Field water management in transplanted rice plots

Substantial yield losses can be expected if these guidelines are not followed or if they cannot be

rice needs no water during the last half of the maturity phase (from dough stage

(according to the planning for herbicide


Reference 7Field water management

Consequences of inappropriate water management

few tillers whereas the absence of water during this phase favors weed growth development and may

Bibliography

Field

Crops Research

Manuel pratique pour la riziculture

Figure 7.2. Excess water

reduces tillering


Reference 8 Knowing the rice plant

Summary

This reference provides insight into the origin, taxonomy, growth and development of the rice plant. Such

for a good analysis of production problems and opportunities, and sound decision-making.

Origin and taxonomy

genus Oryza Oryzae

Oryza

sativa Oryza glaberrima

O. sativa, of Asian origin, comprises

indica and japonica

indica type from tropical Asia is usually

Several secondary ramifications (small

japonica type, from temperate and

Oryza glaberrimaa

Nowadays, the Asian species (O. sativa O. glaberrima ,

mainly because of its higher yield potential.

Figure 8.1. Example of an Oryza sativa plant type


Reference 8Knowing the rice plant

Structure of the plant

Vegetative organs

Roots

Stems

internodes, the more resistant the plant will be to

is to transport water and nutrients and to bring

of the main stem, other stems, called secondary

Figure 8.2. Comparison of panicles of Oryza glaberrima (right) and O. sativa (left)

Figure 8.3. Vegetative organs


Leaves

sheath

auricle

ligule

O. sativa, but short and round in O. glaberrima

Panicles

It is the top part of the rice plant, carried on the

branches themselves carrying the pedicels which

are variety differences in length, shape and angle

Flowers

Grain or paddy


Figure 8.4. Rice panicle (O. sativa)


Growth and development stages of rice

comes to an end after going through the following ten

Germination

when the coleoptile appears, from which will develop

emergence of either the coleoptile or the radicle to the

Seedling

first leaf to the emergence of the fifth

Tillering

which the seedling produces tillers.

stage starts with the emergence of the

tillers degenerate and the number of tillers


Figure 8.5. Rice grain

Figure 8.6. Germination (a), emergence (b) and tillering (c)


Internode elongation

comes to its end, the plant’s internodes start to grow,

Panicle initiation (PI)

that emerges inside the bottom of the last node, is

maximum tillering, internode elongation, and panicle

occur in the above-mentioned order in medium- to

some constants are inherent to variety, temperature and

Panicle development

by the swelling of the bottom of the panicle leaf, which

After initiation, the panicle grows towards the top of the

by the emergence of the panicle from the bottom of the

on progressively until the panicle has completely

called lodicules, situated at the bottom and inside the grain, which dilate with warming, at the same

time pushing apart the two

as the husks are open, the stamens stand up, and because of the outside temperature, the anthers dry out


Figure 8.7. Internode elongation

Figure 8.8. Method to determine the moment

of panicle initiation

Exposing the developing

panicle by longitudinal

sectioning of the main

stem

Position of the

developing panicle in the

main stem


Milky stage

Dough stage

Maturity

The development phases of the plant

Vegetative phase

Reproductive phase

Maturity phase

The vegetative phase: During the vegetative phase, the plant goes through the following stages of

Figure 8.9. Development of the panicle


Spikelet development

(stem elongation)

Panicle initiation

Flag leaf

Figure 8.10.


during the vegetative phase, the most important being weed control (either by weeding or chemical

The reproductive phase:

The maturity phase:

susceptible to climatic hazards, such as, for instance, high temperatures, violent winds, and drought

or stopping irrigation once the dough stage has been reached will not have negative consequences

Bibliography

Science of the rice plant. Physiology

Fundamentals of Rice Crop Science


Figure 8.11. The three main phases of rice development


Reference 9 Seed production

Summary

of an acceptable quality if they follow the recommendations below, a system referred to as community-

Recommendations to improve seed quality

Producing seeds begins a long time before harvest, as at maturity stage it is often too late to distinguish

Drying

Avoid drying on tarred roads, as this may damage the seeds because of the abrupt increases or


Reference 9Seed production

Threshing

If threshing is done with a machine, one should check that the thresher has been carefully cleaned

Storing

Granary storing in the savanna zone:

caïlcedrat

(Khaya senegalensis


Reference 9Seed production

Germination test

After about a week, unfold the cloth and count the number of grains that germinated and

–

–

–

Bibliography

Système semencier communautaire : cas de la riziculture

traditionnelle. Guide du technicien

Système semencier communautaire. Guide du riziculteur : comment

améliorer la qualité de la semence ?


Reference 10 Selecting a variety

Summary

Selecting the right variety depends on what constraints a farmer is facing (e.g. disease or iron-toxicity problems,

African rice (Oryza glaberrima) and Asian rice (O. sativa subsp. indica), are expected to play a key role in rice

cropping in inland-valley lowlands. Participatory Varietal Selection (PVS) is an effective tool to allow farmers

to select varieties that suit their needs.

systems be consulted to gain knowledge of what varieties have been released for inland-valley lowland

rice (Oryza glaberrima O. sativa indica

Variety Ecology Height (cm) Growth Characteristics

duration (days)

Bouaké 189 Inland-valley 115 135 High yield

lowland

WITA 1 Inland-valley 115 130 Tolerance to iron toxicity;

lowland resistant to blast; high yield

WITA 3 Inland-valley 105 125 Tolerance to iron toxicity;

lowland resistant to blast; high yield

WITA 7 Inland-valley 115 130 Tolerance to rice yellow

lowland mottle virus (RYMV); high yield

WITA 8 Inland-valley 112 125 Tolerance to RYMV; high yield

lowland

WITA 9 Irrigated and 95 120 Tolerance to RYMV; high yield

inland-valley

lowland


Reference 10Selecting a variety

it is crucial to involve farmers in the selection of varieties to ensure that such varieties respond to their

see next page

Bibliography

Participatory Variety Selection (PVS): Facilitators’ Guide.


Reference 10Selecting a variety

Table 10.2. PVS-R, PVS-E and CBSS involvement in the seed selection–diffusion

Introduction PVS-R PVS- E Homologation CBSS

Year 0 Interesting

varieties

Year 1 Rice garden

Year 2 Year 1 of farmer

tests

Year 3 Year 2 of farmer

tests 3–4 most selected Year 1 multi-location Pre-basic seeds

varieties compared experiments (station)

with local variety

Year 4 3–4 most selected Year 2 multi-location Basic seeds

varieties compared tests and diffusion (station)

with local variety

Year 5 Beginning of CBSS

program


Reference 11 Effects of temperature on rice

development

Summary

Rice phenology (the succession of rice development stages) depends, among other factors, on air and water

temperature and on photoperiod (day-length), and thus changes throughout the year. Phenology is essentially

a function of varietal choice and sowing date. A good knowledge of rice development enables one to predict

the best timing of crop management interventions. The timing of these interventions—e.g. application of

fertilizer, weeding, last drainage before harvesting—is directly linked to rice development. Temperature also

lead to spikelet sterility and, therefore, yield loss.

Rice varieties can be characterized by a base temperaturebase

opt

relatively constant, and a ‘temperature-sum’ sum

base

sum base

opt

example)

Constant Tbase

(°C) Topt

(°C) Tsum

(°C*days) No. days to

10 10 25 1000 –

20 10 25 1000 100

25 10 25 1000 66

30 10 25 1000 66


-season for varieties

Reference 11Effects of temperature on rice development



0 3 4 10 14–15 18–19

S T ST PI F M

9

Sowing date


Bibliography

Science of the rice plant. Physiology

Field Crops Research



Fundamentals of rice crop science

Development stage No. days after sowing No. weeks after sowing

Emergence 3

Start of tillering 20 3

Mid-tillering 40 6

Panicle initiation 60 9

Elongation 80 11

Heading 85 12

Flowering 90 13

Maturity 120 17

Development stage No. days after sowing No. weeks after sowing

Emergence 3

Seedlings transplanted 20 3

Start of tillering 30 4

Mid-tillering 50 7

Panicle initiation 70 10

Elongation 90 13

Heading 95 13–14

Flowering 100 14–15

Maturity 130 18–19



Reference 12 Field preparation before the start

of the rice-growing season

Summary

Rice cropping requires adequate land preparation. Optional operations include land clearing, weeding, pre-

irrigation, plowing and harrowing, and leveling. The reasons for each of these operations are discussed in

this reference.

The operations

inland valleys, the option often chosen is ‘

Clearing and weeding involves cutting the weeds and stacking them on the bunds, or spreading them

Pre-irrigation

Plowing should ideally be done a few weeks before sowing to allow enough time for the weed and


Flooding

Leveling

Bibliography

Rice Production Manual

Rice Production Manual

Reference 12Field preparation before the start of the rice-growing season


Reference 13 The seedling nursery

Summary

A good seedling nursery produces vigorous seedlings. This reference describes how to install and manage

a nursery, from the soaking of the seed to the removing of the seedlings ready for transplanting.

Seed pre-germination

Preparation of the nursery

removal of seedlings, but the nursery should not be too

sandy either, to prevent seedlings from drying out too

After puddling and leveling the area that will be used for

serve as pathways for transplanters to pull the seedlings,

sowing beds


Nursery site

Sowing density

of seeds per m

Make sure that good-quality seeds are used (germination test, see

Make sure that irrigation is well managed and protect the beds from birds, other animals and other

Seedling age

recommended that transplanting be done when seedlings are two to three weeks old during the rainy

Nursery water management

Reference 13The seedling nursery


During the dry season, it is advisable to drain the plot in the evening to avoid exposing the young

Nursery fertilization

In case of poor soil fertility, or during the dry season, when growth is slower, it is recommended that

Pulling seedlings

Pulling rice seedlings is a delicate operation that is too critical to be left to children (which is often the


Figure 13.2. Water management in the nursery


Bibliography




Reference 14 Plant nutrients

Summary

This reference is about the importance of nutrients for rice production and the symptoms of nitrogen,

for Reference 15 (integrated soil-fertility management).

Essential nutrients

Nitrogen

stunting and a uniform yellowing of the plants (see


Reference 14Plant nutrients

Phosphorus

see

Potassium

Potassium also plays an important role in the resistance to some stresses such as drought, insects

margins, and small brown spots (see



Micro-nutrients

Zinc

(see

Zinc application

Bibliography

Rice. Nutrient Disorders and Nutrient Management

Rice. A Practical Guide to Nutrient Management

Science of the Rice Plant. Vol. II Physiology

Fundamentals of Rice Crop Science


Reference 15 Integrated soil fertility management

Summary

Integrated soil fertility management (ISFM) aims at the optimal and sustainable use of soil nutrient reserves,

mineral fertilizers and organic amendments. We explain in this reference how to calculate mineral and organic

phosphorus, P; potassium, K) and taking into account yield potential (determined by cultivar choice, sowing

and the relation between such analyses and rice growth is often poor, especially for nitrogen. This reference

offers another method to determine the soil nutrient-supplying capacity. The rice yield from a mini-plot, with

2O

5/ha and

18 kg K2 2

O5/ha and 60

kg K2

of 20% for P. The recovery rate is the percentage of fertilizer effectively absorbed by the plant as compared

to the quantity applied. These relations are approximate and only valid for yields not exceeding 70 to 80%

of the potential yield. For higher yield targets, more nutrients have to be applied to get the same return, and

recovery rate of this nutrient. The recovery rate of nitrogen is strongly related to crop management. This

reference provides instructions to help increase this recovery rate. For P and K, losses are much less (P and

K are absorbed by the soil), and the residual effect of the fertilizer applied is often visible several years after

application. Organic fertilizer can, to a certain extent, replace mineral fertilizers, but large quantities need to be

applied as organic fertilizers have a low nutrient content. However, using both mineral fertilizers and organic

and in some cases increasing the recovery rate of mineral fertilizer nutrients.

Soil fertility depends on the soil’s origin (alluvial soils, soils derived from different types of parent

to store nutrients and to release them gradually to the plant roots, because they are composed of very


decomposed soil organic matter and of available clay particles together form the exchange complex

An increase in the organic-matter content cannot be reached within one or two cropping seasons, it is

Soil-fertility management is crucial for maintaining or increasing the yields and incomes of the majority

instance, the incorporation of crop residues in the soil and fertilizer application increase nutrients in the

is increasingly being abandoned in Sub-Saharan Africa, where farmers are obliged to intensify their

soils are in general more robust and fertile than upland soils, but poor soil-fertility management of

Reference 15Integrated soil fertility management


Nutrient stocks in the soil

Box 15.1. How to estimate soil nitrogen reserves

For light-textured soils, 1 liter of soil weighs about 1.5 kg. Clayey soils tend to be heavier: about 1.7 kg/L of dry soil.

The volume of 1 ha of soil with a depth of 0.2 m is:

10,000 m2 × 0.2 m of depth = 2000 m3 of soil, i.e.

2000 × 1000 L = 2,000,000 L

This equals 2,000,000 × 1.5 kg of soil = 3,000,000 kg. A soil with a good supply of nitrogen contains about 0.1% nitrogen,

i.e. 1 ha will contain about 3,000,000 kg × 0.1/100 = 3000 kg of nitrogen. Out of this, 1500 kg (50%) represents the

Estimation of nitrogen reserve (N) in the root zone (depth: 0.2 m)

(kg/ha) (kg/ha) (kg/ha)

Good level > 0.1 > 30 > 1500 1500

Low level 0.05–0.1 15–30 750–1500 750–1500

Very low level < 0.05 < 15 < 750 < 750




Box 15.2. How to estimate soil phosphorus reserves in the soil

Assuming we use the same soil as in Box 15.1. If soil analytical data indicate a P-Bray content (a proxy for plant-

available P) of about 6 mg/kg, a total of 3,000,000 × 6 = 18,000,000 mg of P is available for the crop per hectare, or

18 kg of P per hectare. Total reserves in the soil are much more important. If soil analytical data indicate a P-total of

800 mg/kg, total reserves are about 2400 kg/ha.

Estimation of phosphorus reserves (P) in the rooting zone (depth: 0.2 m)

P level in soil P-Bray P-total

Laboratory data Available for crop Laboratory data Total reserves

(mg/kg) (kg/ha) (mg/kg) (kg/ha)

Good > 25 > 75 > 800 > 2400

Average 6–25 18–75 200–800 600–2400

Low 3–6 9–18 100–200 300–600

Very low < 3 < 9 < 100 < 300

Box 15.3. How to estimate the availability of potassium in the soil

Assuming we use the same soil as in Box 15.1. If laboratory data indicate a 0.10 cmol/kg of exchangeable K (a proxy

of K is equivalent to 39 grams, i.e. 1 cmol is equivalent to 0.39 grams of K. A ratio of 0.10 cmol/kg of exchangeable

K represents for this soil a quantity of (3,000,000 × 0.1 × 0.39)/1000 = 117 kg of K/ha. The reserves in K are usually

much higher, but can be very variable.

Estimation of potassium (K) available (exchangeable K) in the rooting zone (depth: 0.2 m)

K level in soil Exchangeable K

Laboratory data Available for crop

(cmol/kg) (kg/ha)

Good > 0.25 > 300

Average 0.10–0.25 120–300

Low 0.05–0.10 60–120

Very low < 0.05 < 60


Mineral fertilizers

Nitrogen fertilizers

see under

3

Phosphorus fertilizers

P , is

Potassium fertilizers

kg

Organic amendments

manure is that it increases the N content, improves the soil structure and increases the organic-matter

Mucuna pruriens is a rapidly growing legume,

Sesbania rostrata,



Sesbania sesban, Tephrosia vogelii and Crotalaria

organic amendments often results in synergistic effects, increasing soil nutrient-supplying capacity in

Integrated soil-fertility management aims at the optimal and sustainable use of nutrient stocks from the

Fixing a yield target

max

max

a sowing date that will allow him or her to exploit the weather conditions more productively and to

max can be obtained on experimental plots conducted

under optimal growing conditions, where plant growth and development are not limited by factors

max is the real yield ceiling, limited by climate, sowing



a max f

bf

f max a bf f

max

yields is often neither economical nor realistic, especially when water management is not optimal (in

Estimate the capacity of the soil to supply N, P and K

Figure 15.1. Yield gaps between average yield (Yf bf

),

attainable yield (Ya) and potential yield (Y

max)

Average farmer yield (Yf)

Yield of best farmer (Ybf)

Attainable yield (Ya)

Potential yield (Ymax

)

Yield gap 3

Yield gap 2

Yield gap 1

Determining factors

solar radiation,

temperature, varietal

characteristics, sowing

date

Limiting factors

Water, nutrients

Reducing factors

Sub-optimal management;

poor emergence, very old

seedlings at transplanting,

weeds, diseases



Table 15.1. The principle of zero-N, zero-P and zero-K plots

Mini-plots N P K

growth (the exact amount will depend on the growth conditions, one may refer to recommendations currently

used by extension staff, or to what is done by the best farmer).


Figure 15.2. Example of yields obtained in zero-nutrient plots, potential yield and target yield

Y-max = potential yield

Y-target = target yield

adequate doses of P and K

Y-0P = yield obtained without P but with

Y-0K = yield obtained without K but with


Calculating fertilizer requirements

Nitrogen

N-fertilizer is lost because of many constraints, such as late urea application, weed pressure and

see

Table 15.2. N, P and K concentrations in rice grains and straw (%)

N P2O

5K

2O

Grain 1.0 0.4 0.3

Straw 0.5 0.2 1.5



Phosphorus

kg P

Potassium

Box 15.4. Increasing the recovery rate of nitrogen

Using good-quality seed (Reference 9).

Transplanting seedlings at the right age (References 13 and 16).

Using a plant spacing that is adequate for the variety used, usually 0.2 × 0.2 m.

Removing weeds before fertilizer application.

Using pest and disease control.

Harvesting on time, at maturity.

apply at tillering and panicle initiation.

20%, respectively, at the start of tillering, at panicle initiation and at heading.

Using a good application method:

- Lower the water level to a strict minimum (about 3 cm);

- Broadcast in a homogeneous way (without incorporation);

- Irrigate again 4 to 5 days later.

To maximize fertilizer uptake by crops, fertilizer should be applied in a homogeneous way, when needed, after weeding

will increase.



Avoid soil nutrient mining!

well-managed mini-plots can become a means of evaluating the evolution of soil fertility in farmers’

Careful! Even if the yields of the small zero-nutrient plots do not indicate the need to apply fertilizer,

it is possible that a maintenance application is necessary to prevent soil fertility from being mined over

Combining organic amendments and mineral fertilizers is often the best strategy for maintaining or

Bibliography

Journal of Plant Nutrition and Soil Science

In Managing Soil Fertility in the

Tropics: A Resource Guide for Participatory Learning and Action Research

Rice. Nutrient Disorders and Nutrient Management

Field Crops

Research

Rice. A Practical Guide to Nutrient Management


Agricultural Systems

Field

Crops Research



Reference 16 Transplanting

Summary

These are the main reasons why farmers mostly transplant, rather than direct-seed rice in inland valleys. This

reference will provide guidelines to consider when transplanting rice seedlings.

common problem in inland-valley lowlands that are often poorly leveled and without adequate water

bottom node cannot produce tillers as it is deprived of

that case to develop a second node, a little higher on the

Figure 16.2. Transplanting depth should be about 3 cm to

favor tillering from the bottom node

Figure 16.1. Transplanting


Transplanting mode and density

the canopy cover that has been obtained at panicle initiation, as this is the start of the reproductive

cover at panicle initiation and solar radiation will, therefore, not be optimally used (light is hitting the

Transplanting along a line

Random transplanting

than transplanting using a line or other device, and it does not require synchronizing work as for

Replacement of missing hills

Seedlings that are pulled from the nursery may be damaged to such an extent that they do not survive

Bibliography


Reference 16Transplanting


Summary

This reference presents six important steps to promote farmer experimentation: (i) meeting for consensus-

building and planning, (ii) lay-out of the experiment, (iii) monitoring of the experiment, (iv

(v) managing and analyzing the data, and (vi) evaluation.

group of test-farmers within the group of farmers following the PLAR for integrated rice management

objectives as hypotheses, which will help them design the experiment and specify the information to be

guidelines and use a systematic approach so that the results of the experiments can be analyzed and


Reference 17

Description Objectives Expected outputs

Step 1

Planning meeting

and designing, monitoring and

evaluating experiments

To agree on procedures for

experimental designs and for

monitoring the experiments

Experiments designed

An agreed procedure for the lay out

and monitoring of the experiments,

including the roles and responsibilities

of the PLAR-IRM team and test-farmers

Step 2

Lay-out of the experiment

To train the farmers how to lay out

experiments

To allow farmers to implement the

experiment on their own

To agree on procedures for

experimental designs and for

monitoring the experiments

Test-farmers trained to lay out

experiments themselves

Facilitators and farmers agree on

procedure for monitoring experiments

Step 3

Monitoring of the

experiment

To see how the experiment

performs

about the experiments

To collect the information needed to

performance

performance

their reasons for them

Data to enable analysis of the

Step 4

Field visits

To encourage participating farmers

to exchanging their experiences

To share information among test-

and non-test-farmers (within and

between villages)

All test-farmers to be well-informed

about new techniques

experiments conducted

Information exchanged between

farmers and PLAR-IRM team

Step 5

Managing and analyzing

data

To enter and process data

To analyze data

To organize results in tables,

To summarize results, so that

farmers can easily understand them

Data processed on computer

spreadsheets

Data analyzed

Results accessible for farmers

Step 6

results with farmers

To present the results of data

analysis

To gather what farmers think about

the results

To identify suggestions for follow-up

All farmers informed about the results

of data analysis

List of suggested follow-up activities


Reference 17

be as simple as possible and the different treatments will be preferably lined up and separated by

Depending on how the farmers view experimentation, some aspects will receive more attention than

others. The experimentation will allow farmers and the PLAR-IRM team to

Compare the results obtained by different test-farmers, thereby increasing the farmers’ learning

Draw conclusions about the effectiveness of the techniques and practices tested (involving statistical

help explain the different results obtained by different farmers, and should also improve how future


It is very important to know, and to assess, what farmers think of the new practice or technique

between farmers and the PLAR-IRM team should lead to a consensus on how to lay out and monitor

the experiment, and to an agreement about the roles and responsibilities of the test-farmers and the

have to be adapted to the prevailing conditions, which implies that the training session should review

followed, by the lay-out itself being implemented by the participants and a member of the PLAR-

Monitoring is an integral part of the experimentation phase since it provides information that is needed

Reference 17


Data related to the performance of the new practice or technology (also called farmers’ indicators

If illiteracy is widespread among the participants, they should use forms and symbols to assess the

to be qualitative and is often only recorded on an irregular basis, depending on the farmer’s curiosity

If the farmers’ experiments are part of a wider research program, the PLAR-IRM team will also have

to record data and should visit each site regularly, noting their observations on a pre-established

are monitored not only on the individual test-farmer plots, but also at farmers’ meetings during which

Reference 17


to better understand results obtained by test-farmers and discuss with them the practices that have

All the information collected in the course of the experiment is summarized on a monitoring sheet

see

Analytical results are most commonly presented in tables, charts and graphs, with quantitative and

the results and to discuss what they think has caused the differences between results obtained by

management seems to be the major cause, it is important to identify why some farmers have managed

Reference 17


should be encouraged to discuss why some are in favor of the practices being tested and others are

might decide to reject the new practice or to try it out for a second season, possibly with an adapted

Bibliography

Managing Soil Fertility in the tropics: A Resource Guide for participatory learning and action research

Conducting on-farm experiments

Developing technology with farmers: A training guide

for participatory learning

Reference 17


Reference 18 Getting acquainted with weeds

of rice

Summary

Weeds can be divided into three groups: grasses, sedges and broad-leaved weeds. Good knowledge of

on the actions to take (see References 19 and 20).

may act as alternative hosts for insect pests, but also for their natural enemies (see

Grasses

thin leaves, usually with parallel vein, and the round and hollow stems are composed of segments

Common annual grass weeds are Echinochloa crus-pavonis, E. colona and Ischaemum rugosum

Sedges

Cyperus

difformis, Cyperus iria and Kyllinga pumila


Figure 18.1. Three widespread grasses found in inland valleys

Figure 18.2. Three common sedges found in inland valleys

Echinochloa colona (L.) Link Echinochloa crus-pavonis (Kunth)

Schultes

Ischaemum rugosum Salisb.

Cyperus difformis L. Cyperus iria L. Kyllinga pumila Michaux

Reference 18Getting acquainted with weeds of rice


Broad-leaved weeds

Ludwigia abyssinica,

Sphenoclea zeylanica, Ipomea aquatica and Heteranthera callifolia

Bibliography

Weeds of Rice in West Africa / Les adventices en riziculture en Afrique de l’Ouest/

Reference 18Getting acquainted with weeds of rice

Ludwigia abyssinica A.

Rich.

Ipomoea aquatica

Forssk.

Sphenoclea zeylanica

Gaertner

Heteranthera callifolia

Rchb. ex Kunth

Figure 18.3. Four broad-leaved weeds dominating in inland valleys


Reference 19 Integrated weed management

Summary

Integrated weed management consists of the combination of different control methods, in order to ensure

good control of weeds. Combination of methods does not mean that they are simultaneously applied. There

are preventive and curative methods, and the combination of different practices will depend on the weed

socio-economic environment and on his technical level of expertise. For technical and economic reasons,

integrated management should be used rather than any single method on its own. Several weed management

methods are treated in this reference.

Preventive control methods

Oryza glaberrima

and Asian rice (O. sativa indica

Crop management techniques


Direct underwater sowing of pre-germinated seeds, while maintaining the water level, reduces weed

proven that Echinochloa

Curative control methods

in rows, as the rotary hoe, the daba

Roguing is the removal of any plant—including weeds, rice off-types and wild rice—other than the

Bibliography

Weeds of Rice in West Africa / Les adventices en riziculture en Afrique de l’Ouest

Reference 19Integrated weed management


Reference 20 Safe and correct use of herbicides

Summary

inadequate. As a result, the effectiveness of herbicides is often low, resulting in persistent weed growth, health

problems for farmers and environmental pollution. This reference gives guidelines on safe and well-informed

use of herbicides. Many integrated weed management options other than herbicide use are available to

farmers and, as much as possible, these options should be promoted or combined with herbicides to reduce

If not correctly used, herbicides may be dangerous to the health of the farmer, his or her crops, and

Choice of product

as indicated, they will control susceptible weeds without damaging the crop for which they are

Contact herbicides kill parts of the plant that the product comes into direct contact with when


commercial

common chemical name of the active compound

see

Treat at the appropriate time

Reference 20Safe and correct use of herbicides

It is important to follow the directions that are usually printed on the label of the



Do not forget the water!

Sprayer nozzle

Cone nozzles should be used with higher pressure settings and fan nozzles should be used with lower

Figure 20.1. Different nozzle types

Cone nozzle (insecticides) herbicides)

Figure 20.2. Example of the effect of nozzles in good and bad

working condition on the application of herbicides



Dosage

tried to simplify calculations by calculating the number of sprayers per hectare to apply and by using a

The small tomato can

Take care!

Use the right application techniques



DO DO NOT

Contaminate waterways and drains with


Safety rules to be respected

Do not let children handle herbicides or their containers.

Wear gloves, glasses and a mask while treating.

Wash carefully with soap after touching the herbicide bottle and after treating.

Clean clothes and equipment with soap.

If the solution enters the eyes, rinse with lots of water and go as quickly as possible to the nearest health center

(clinic).

Dispose of empty containers carefully.

Figure 20.3. Use gloves, a mask and glasses during herbicide spraying. Wash your body, the

equipment and clothes with soap after using herbicides



Table 20.1. Herbicides used for weed control in inland-valley rice and guidelines for application

Names Active

ingredients

(g/L)

Target weeds Stages Dosage

(L/ha)

When to

apply

Obser-

vations

Propanil

Stam F 34

Surcopur

Propanil: 360 Grassesand some broadleavedweeds

2–3 leaf stage of weeds

5 to 8 After drainage Contactherbicide

Weedone TP

2,4-D: 480 Broad leaves and sedges


1 to 1.5 After drainage Contactherbicide

BasagranPL2

Bentazon:140

Propanil: 360

Broad leaves and sedges


6 to 8 After drainage Contactherbicide

Garil Triclopyr: 72

Propanil: 60

Grasses,sedges and some broad-leaved weeds


5 After drainage Contactherbicide

Ronstar12 L

Oxadiazon:120

Grasses,sedges and broad-leavedweeds

Beforeemergence of rice and weeds

6 Apply on water layer, three days after sowing or transplanting

Contactherbicide

Ronstar PL Oxadiazon:120

Propanil: 360

Grasses,sedges and broad-leavedweeds

After emergence of

rice and weeds

5 After drainage Contactherbicide

Ronstar 25 EC

Oxadiazon:120

Grasses,sedges and some broad-leaved weeds

Beforeemergence of rice and weeds

4 Apply on moist soil

Pre-emer-genceherbicide

Londax Bensulphu-

ronmethyl

Sedges and broad-leavedweeds


80 g/ha Applied to the Applyusing a bottle



Reference 21 Insects in rice cropping

Summary

Insects can be either harmful or useful to rice cropping. The integrated management of insects, in which the

use of insecticides is reduced to the minimum, requires good knowledge of their development cycles. This

reference describes the main families of insects that are either harmful or useful to rice cropping, details their

development cycles, and presents methods for the integrated control of harmful insects. The dangers of using

and manipulating insecticides is also presented.

An ecosystem is a natural environment made up by dynamic interactions between biotic and abiotic

of the agro-ecosystem is maintained, the populations of insect pests can be kept to levels that are easy

an important mechanism of protection—maintaining the balance among all the elements in the

Biodiversity

A healthy ecosystem has a high degree of diversity, in terms of the number of species and the genetic


that increase soil fertility and ‘natural enemies’ like spiders, scale insects, frogs and lizards, which

Natural enemies

Large animals usually live longer and have fewer offspring, while smaller animals have shorter life

What is a natural enemy?

Predators

Parasites

Predators

Parasites

Reference 21Insects in rice cropping


Pathogens

Pardosa Lycosa Wadicosa

Thomisus

Tetragnata

or Argiope

Gasteracantha

Pholicus

Salticus

(Table 21.1)



Tab

le 2

1.1

. In

sects

in

ric

e c

rop

pin

g

Nam

e o

f

dam

ag

e

Ord

er/

Fam

ily/

Sp

ecie

s

Typ

e o

f d

am

ag

eS

ym

pto

m

descri

pti

on

Sta

ge o

f

insect

cau

sin

g

dam

ag

e

Su

sc

ep

tib

le

pla

nt

sta

ge

Imp

ac

t o

n

yie

ld

Ric

e Y

ello

w

Mottle

Virus

(RY

MV

)

Cole

opte

ra

Locusts

Leafh

oppers

Leaf

destr

uction

Cut

leaves

Perf

ora

ted s

pots

with

min

ute

str

ips

Early y

ello

win

g

Stu

nting

Adult

Ve

ge

tative

sta

ge

,e

ve

n w

he

n

tra

nsp

lan

ted

So

me

tim

es

no

yie

ld a

t a

ll

Onio

n tube

Fly

(A

fric

an

Ric

e G

all

Mid

ge)

Som

e leaves

change into

yello

wy-w

hite

tubes,

lookin

g lik

e

onio

n leaves

Larv

a (

sm

all

yello

w w

orm

)V

eg

eta

tive

sta

ge

So

me

tim

es

no

yie

ld a

t a

ll

Dead h

eart

bla

ck a

nte

nnae:

Dio

psis

and

Chilo

,S

esam

ia,

Scirpophaga

Som

e leaves

change into

yello

wy-b

row

ntu

bes c

alle

d d

ead

heart

Pla

nts

can b

e

pulle

d u

p e

asily

Larv

a (

sm

all

yello

w w

orm

)E

arly

ve

ge

tative

sta

ge

Hig

h y

ield

d

esp

ite

att

ack

Defo

liation

Sm

all

white

Nym

phula

Many leaf

fragm

ents

they a

re t

he

sheath

s/

covers

that

pro

tect

the larv

ae

Tip

s o

f rice leaves

are

cut

Fie

ld w

hitenin

g

Larv

aE

arly t

ille

ring

usu

ally

reco

ve

rw

ith

ou

tlo

sse

s

Destr

uction

of ro

ots

Term

ites

Mic

rote

rmes

Macro

term

es

Early y

ello

win

g

and d

ryin

g o

f le

aves

Adult t

erm

ite

“work

ers

”A

ny t

ime

in

cycle

w

he

ne

ve

rw

ate

r is

la

ckin

g

Lo

sse

s m

ay

be

hig

h

Gra

inbla

ckenin

gS

tinkin

g b

ugs

Aspavia

lepto

cory

sa

Sm

all

bla

ck o

r bro

wn

spots

on g

rain

sB

ad g

rain

qualit

y

(colo

r, f

ragra

nce,

Adult

Re

pro

du

ctive

sta

ge

an

d

ma

turity

Sm

all-

sca

lein

dire

ct

losse

s



Chilo spp., Maliarpha separatella, Sesamia calamistis, Nymphula depunctalis, Eldana

saccharina, Scirpophaga Diopsis Orseolla oryzivora, the

Stem borers cause the worst damage, as they infest rice plants from the seedling stage to maturity,

(see

see also

when the plant has already reached an advanced stage of development, the older caterpillar embeds

then shows through the drying of some of the spikelets, leading to a decrease in the number of grains

Defoliators


Adult

Larva

Cocoon Egg


Nymphula depunctalis.

of the lack of turgidity, the leaf fragment wraps itself around the caterpillar, which then closes the part of

the leaf that is almost cut off with a few silk threads, cuts the part that is still attached to the remainder

Cnaphalocrosis medinalis, Marasmia trapezalis, Diacrisia scortilla,

Parnara spp., Hispides spp.

Piercing–sucking insects

Root cutters

Rice mole cricket

Termites

Microtermes, Macrotermes and Trinervitermes

Water weevils



Storage pests

Stored rice can be attacked by a wide range of insects whose identities and cycles differ from those

Insect control

Crop management practices

Biological control

keep Paspalum scrobulatum



straw leads to an increase in spider populations which hide there during the day, and at night hunt the

Some other biological control methods can also be used, including in particular the promising use of

Chilo suppressalis and Chilo

zacconius

interesting as they may also help ‘predict’ infestations and help choose which kind of control to use,

as pheromones allow the detection of very small populations of insects, especially before they begin

it often demands relatively complex management, and requires rather high investments and a certain

Genetic control

Chemical control

Integrated insect control

Integrated insect control means that the populations of harmful insects will be kept as low as possible so



Pesticides and natural enemies

What is a pesticide?

natural enemies, and even animals or humans may fall ill or die because they came into contact with

poisons

doing so, we remind ourselves and others that pesticides are dangerous and that their use ought to be

Pesticides, natural enemies and harmful insects

Most farmers have noticed that the problems with insect pests like aphids and other small insects



which means that natural enemies need a longer period to recover and thus for their population to

Pesticides and human health

the effects can become chronic and the symptoms may be blood-pressure changes, heart problems,

Some safety rules

If, by accident, the product comes into contact with the eyes, nose or mouth, rinse with abundant

water and go to the closest health center, if possible, with the references of the product (packaging



Bibliography

Manuel sur les principaux ennemis du riz en Afrique de l’Ouest et leur contrôle

in press Rice-Feeding Insects and Selected Natural Enemies of West Africa:

In press.



Reference 22 African rice gall midge

Summary

This reference complements Reference 21, which presented an overview of the insect pests and useful

insects. African rice gall midge, Orseolia oryzivora, causes such severe damage to rice crops and has such

a complex behavior that it requires a special reference. This reference provides more detailed information

about the insect to help the facilitators develop a strategy to control it. This reference presents the life-cycle

of African rice gall midge and also some integrated control methods.

Description

In the inland valleys in Sub-Saharan Africa, African rice gall midge (Orseolia oryzivora

The egg

The larva

The pupa

The adult

Biology and damage

At hatching, the larva makes its way down between the leaf sheaths and the stem to the growing point


Recognizing gall midge damage

conspicuous, either because they are hidden by the rice leaves, or else because they are green under poor

Orseolia oryzivora

Oryza

barthii, O. longistaminata, see

Control


Destruction of wild rice, O. longistaminata

Preservation of Paspalum scrobiculatum (see

Platygaster diplosisae and Aprostocetus procera

Reference 22African rice gall midge


Biological control

Platygaster diplosisae and Aprostocetus

procera

Paspalum scrobiculatum

Indeed, during the dry season, Platygaster diplosisae and Aprostocetus procera develop on the other

midge species on Paspalum scrobiculatum

lay their eggs inside the midge eggs, larvae and pupae, thus killing the gall before it reaches the adult

Platygaster diplosisae attacks the eggs and the larvae of gall midge on the outside of the rice

plant, and Aprostocetus procera Paspalum

scrobiculatum, they destroy at the same time the useful insects Platygaster diplosisae and Aprostocetus

procera Paspalum Oryza

longistaminata


Figure 22.1. Oryza barthii Figure 22.2. Oryza

longistaminata

Figure 22.3. Paspalum

scrobulatum


Control through varietal resistance

ability to resist can result from the morphological constitution discouraging the insect (hard plant

Oryza sativa O. glaberrima

O. sativa

O. glaberrima and O.

sativa

Bibliography

Manuel sur les principaux ennemis du riz en Afrique de l’Ouest et leur contrôle

Weeds of Rice in West Africa / Les adventices en riziculture en Afrique de l’Ouest

Rice Stem Borers:

Biology, Ecology and Control – Field Guide and Technical Manual

African Rice Gall Midge Research Guide



Reference 23 Rice stem borers

Summary

This reference presents the life-cycle of rice stem borers and how to implement integrated control management.

Because of the damage they produce on rice crops, this reference is entirely devoted to stem borers. This

reference complements Reference 22 dealing with African rice gall midge and Reference 21, which presents

an overview of insect pests and useful insects.

Lepidopteran borers

Biology

In general, the eggs of lepidopteran borers stick to the leaves or are sunk between the leaf sheath and the

move on the surface of the plant and migrate to neighboring plants by hanging down from a silk thread

In young plants at the beginning of, and during, tillering, caterpillars enter the leaf sheaths at the

see

see

Stem borer can also induce abortion or drying up of a part of the panicle, when an older caterpillar

settles in the lower parts of the stem, which hinders the feeding of the panicle, resulting in a reduced


Reference 23Rice stem borers

Chilo zacconius Blez.

Chilo zacconius

Proceras africana Chilo

Description

night (see

Echinochloa Oryza barthii,

Sorghum arundinaceum Chilo species, including C. diffusilineus

and C. aleniellus

Maliarpha separatella Rag. or white borer

Description



Maliarpha separatella Oryza

wild rices (O. barthii, O. longistaminata and O. punctata

as it hatches in the morning, the caterpillar moves actively from one plant to another, hanging from a

and the stem, moves down and goes deeper into the sheath, and then into the stem above an internode,

cavities in its wall, but never piercing it, moving from one internode to another, piercing the nodes one

Sesamia sp. (pink borer)

Description

plant and on the abundance of the insect, and looks like the damage caused by Chilo


Dipteran stem borers

Dioposis thoracica W. (Syn. D. macrophthalma Dalman)

Description

see

on the rainy season, Diopsis thoracica

precocity and intensity of infestation, on the tillering capacity of the variety, and on development



Methods to control stem borers

losses do not change a lot year after year, it is possible to establish systematic intervention procedures

Chemical control

Diopsis


Chilo zacconius by synchronized planting over large

Stubble plowing

Fallowing

Destroying

Flooding

application favor good plant development and the resistance of the crop, but they can increase infestation

Biological control

Among the numerous parasitoids on Sesamia Cotesia (= Apanteles sesamiae

Cameron and the eulophid Pediobus furvus



natural enemies to suppress insect populations, Cameron was imported from Asia

Chilo zacconius

about interactions of indigenous natural enemies before embarking on classical biological control by

Varietal resistance

O. sativa

Diopsis

Chilo zacconius

Maliarpha separattela

African rices O. glaberrima O. sativa O. glaberrima

C. zacconium and

M. separatella

Integrated control aims at keeping the populations of stem borers as low as possible without disturbing

Bibliography

This reference has been adapted from

Manuel sur les principaux ennemis du riz en Afrique de l‘Ouest et leur contrôle.

Rice Stem Borers:

Biology, Ecology and Control – Field Guide and Technical Manual



Reference 24 Major diseases in rice

Summary

This reference presents the causes and symptoms of the three main diseases of inland-valley rice: blast, rice

yellow mottle virus and bacterial leaf blight.

Blast

Pyricularia oryzae

see

to rot, and node blast at the level of the stem nodes (see

blast causes soft rot at node level, the nodes break resulting in different degrees of damage depending

Rice yellow mottle virus

plant is that leaves turn yellow, with alternate yellow and green stripes that give its typical mottled

appearance to the plant (see

tillering, leaf mottle with yellow stripes, incomplete panicle exsertion, the panicle sometimes being


of the beetle group (most important Sesselia pussilla and other vectors such as Chaetocnema

Aulacophora africana, Trichispa sericea and Dicladispa viridicynea

Bacterial blight

Xanthomonas oryzea pv oryza

on the leaves, later these lesions dry and become brown and opaque (see

Bibliography

Rice Yellow Mottle Virus (RYMV) and its Insects Vectors: Ecology

and Control—Field Guide and Technical Manual

Manuel de formation en pathologie du riz

Category Disease name Pathogen

Nature

Blast

Rice yellow mottle virus

Bacterial blight

Magnaporthe grisea

Pyricularia oryzae

RYMV

Xanthomonas oryzae orysae

Fungus

Fungus

Virus

Bacterium

Secondary

pathogens

Brown spots

Leaf blast

Sheath blight

Drechsiera oryzae

Bipolaris oryzae

Gerlachia oryzae

Monographella albescens

Rhizoctonia solani

Thanatephorus cucumeris

Fungus

Fungus

Fungus

Fungus

Sterile fungus

Fungus

Minor pathogens False smut

Bakanae disease

Cercosporiosis

Sheath rot

White gall

Fading color of sheaths

Culm disease

Bacterial stripes

Ustilaginoidea virens

c. oryza sativa

Fusarium moniliforme

Gibberella fujikuroi

Cercospora oryzae

Acrocylindrium oryzae

Corallocytostroma oryzae

Fungi complex

Fungi complex

Xanthomonas oryzae

Fungus

Fungus

Fungus

Fungus

Fungus

Fungus

Fungus

Fungus

Fungus

Bacterium

Reference 24Major diseases in rice


Reference 25 Integrated rice disease management

Summary

Integrated rice disease management is the combination of different methods to control diseases in a cost-

effective way, based on sound environmental management. Pathogen populations are kept at low levels,

Varietal resistance and crop management practices—primary elements of

integrated management

Integrated disease management focuses on varietal resistance, because it is the simplest and cheapest

for blast, the occurrence of new pathogen races or environmental conditions favorable to the disease

varietal resistance is accompanied by preventive measures both favorable to rice and reducing disease

Crop management techniques

Synchronized sowing and transplanting to avoid build up of insect pests that can transmit diseases

Destruction of rice stubbles and vector host plants to avoid pathogen build up and to interrupt the


Reference 25Integrated rice disease management

Chemical control—secondary elements of integrated management

Bibliography

Field Problems of Tropical Rice

Rice Yellow Mottle Virus (RYMV) and its Insects Vectors: Ecology

and Control. A Field Guide and Technical Manual

Manuel de formation en pathologie du riz


Reference 26 Harvest and post-harvest

Summary

Timely harvesting, threshing and drying are essential operations to guarantee an abundant and good-quality

harvest. All the efforts put forth from land preparation onward can be compromised when these operations

are badly implemented. This reference gives guidelines that help avoiding large paddy losses, both in quality

and quantity, during these operations.

Harvesting date

Determining the optimal date for harvesting is the most important factor, as mistakes could lead to

reduced and the quality of paddy will be lower with high rates of broken rice and low processing

Harvesting methods


Drying

Leaving the panicles to dry for too long reduces grain quality and exposes the panicles to rat or bird

Threshing

economic climate in order to better insert them in their production systems (impact, after-sales service,

Storing

Reference 26Harvest and post-harvest


Place wooden pallets directly on the ground, so as to allow good ventilation around and under the

Transferring paddy to the factory

draining before harvesting, and about the drying and threshing conditions, the paddy to be processed

Bibliography

International Rice Research Notes

International Rice Research Notes

Reference 26Harvest and post-harvest


Reference 27 End-of-season evaluation

Summary

The end-of-season evaluation is a very useful tool that helps improve the overall performance of a farm. It

consists of comparing expectations and outcome, and analyzing the differences. An end-of-season evaluation

Elements required for an end-of-season evaluation

numbers obtained at the end of the growing season need to be compared with the predictions at the

Bibliography

Michigan State University International Development Papers

Miscellaneous Fertilizer Studies


Items Quantity Units Unit cost Total cost

Variable costs

Crop management

operations

Plowing

Other

Agricultural inputs

Seeds

Urea

Herbicides

Propanil

Weedone

Other phytosanitary

products

Input transport

Harvest

Bags

Human labor

Harvest

Handling

Harvest transport

Total variable costs

Other costs

Dikes, embankments

maintenance

Other

Total costs (a)

Production value (b)

Net revenue (b) – (a)

Photo pages

Photo 4.1. Symptoms of iron toxicity

on leaves

Photo 4.2. Symptoms of iron toxicity

Reference 4Iron toxicity


Photo 22.5. Symptoms of the African rice gall Photo 22.6. Symptom of the African rice gall

Reference 22



Photo 23.1. Symptom of stem borer:

Chilo zacconius

Photo 23.4. Dipteran stem borer

Diopsis thoracica

Photo 23.2. Symptom of stem borer:


Photo 24.1. Pyriculariosis: symptom

on leaf

Photo 24.3. Rice Yellow Mosaic Virus

Photo 24.2. Pyriculariosis: symptom

Reference 24


Photo 24.5. Bacterial leaf blight Photo 24.6. Bacterial leaf blight

Reference 24



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